Well-casing perforator



Dec. 16, 1930. R. Moss WELL CASING PERFORATOR 2 sheets shet 2 Filed April 15, 1929 MVg/Toa Roscoe floss G'T'TOBNE Y Patented Dec. 16, 1930 UNITED STATES PATENT OFFICE ROSCOE MOSS, OF LOS ANGELES, CALTFORNIA, ASSIGNOR TO ROSGOE MOSS COMPANY,

A CORPORATION OF CALIFORNIA WELL-CASIN G PERFORATOR This invention which is generally indicated as a well casing perforator relates primarily to a punching device which has been produced for the purpose of placing perforations in tubular members at points which under ordinary circumstances are inaccessible.

It is a well known fact that in petroleum or water wells, the outer string of casing which extends to the bottom of the well is commonly provided with a plurality of perforations in the region of the formation or zone containing the petroleum or water. This section of casing is ordinarily termed a screen or strainer casing. Y

In the use of that type of easing commonly known as stove pipe single well casing or double well casing, such as is usually placed in water wells and which has been used to a certain extent in petroleum wells,

this perforated section is ordinarily formed after the casing has been placed within the well, and the means which are in common use at this time for the purpose of providing these perforations or openings in the casing are quite crude and cumbersome and the results obtained are not thoroughly satisfaccasing for the purpose of admitting liquid from the formation.

Although these devices are apparently all right in theory, they are attended by one very undesirable feature in that the ripping action accompanied by the pressure upon the casing from the formation frequently results in the complete rupture of thecasing at the point at which the ripper is used, which obviously admits sand into the casing and stops the flow of liquid into the well.

Further, such devices are generally built in a manner such that the casing is subjected to an unsymmetrical pressure application and a resultant distortion in the region in which the cutting takes place. The size of the openings will, therefore, vary with the casing disnumber of performations without removing 1929. Serial No. 855,074.

tortion, deceiving the operator as to the results obtained.

It is a primary object of this invent-ion to produce a device which is self centering and is operable to form a plurality of small perforations within the casing at any desired point. This is accomplished by providing the device with a series of cutting or wedge members which are adapted to be held iiia transverse plane within the casing and are atthe same time adapted to be moved laterally into engagement with the casing wall. The device is more or less automatic in its operation and may be used to provide any it from the well.

The general construction of this invention embodies a plunger which is preferably hydraulically operated within a cylinder and adapted to operate a suitable mandrel formed in a manner such that a plurality of so-called holding blocks and cutter guide blocks will move laterally into engagement With the walls of the casing when hydraulic pressure is applied to the plunger.

It is a further object of the invention to produce a device of the class described which is provided with means for reducing friction between the sliding blocks in the mandrel.

It might be explained at this time that the term stove pipe casing, as used herein,'.re-

fers to casing of either single or double thickness, which embodies metal sheets bent into cylindrical form, the longitudinal edges of each sheet being attached to one another by means of riveted lap joints or welding.

If a perforating device of the class described was placed in casing of the type referred to above in a position such that one of the cutters engaged the joint in the casing, there would be an unequal stress placed upon the member, also the penetration of the casing would be very diflicult at a point where, the thickness was twice that of any other point.

It is therefore a further object of this invention to produce a device of the class described in which guide means are provided for the purpose of guiding the organization into a position such that there will never be lot ter ideb a cutting member opposite the joint at the use in connection with various casings merely by changing the holding blocks and cutocks. he details in the construction of a preferred embodiment of this invention and further objects attending its production, will be better understood from the following description of the accompanying drawings which are chosen for illustrative purposes only and in which Figgl is an elevational view partly in section s owing the invention as being suspended within a casing, the parts being arranged in inoperative position prior to punching the perforations in the casmg.

Fig. 2 is an elevational section similar to Fig. 1, but showing the parts as having been moved to the extreme position during which the casing is perforated.

Fig. 3 1s a plan section which may be considered as having been taken substantially in a plane represented by the line 33 in Fig. 4 is a plan section taken substantially in a plane represented by the line 4-4 in Fig. 1 and illustrates the details in a construction of a'preferred form of the positionin fingeri T ig. 5 is a partial plan section illustrating the manner in which the invention may be adapted for use in connection with various sizes of casing.

Fig. 6 is a partial elevational section illustrating the perforation which is formed in the casing by means of the invention and Fig. 7 is a partial elevation which may be considered as having been taken substantially in the direction of the arrow 7 in Fig. 6.

More particularly describing the invention as herein illustrated, reference numeral 11 indicates a casing which may be the so-called stove pipe type, having a lap joint which forms a projecting shoulder indicated by reference numeral 12.

The well perforating organization which is generally indicated by reference numeral 13 embodies a cylinder 14: supported between cylinder heads 15 and 16 which are retained in a fixed position relative to the cylinder in any suitable well known manner,'such as by means of the tie rods 17.

The cylinder 14 is supported within the casing by means of a tubular supporting member or fluid delivery tube 18, which 1s hollow plunger rod mounted in the cylinder head 16 and is adapted to receive the upper end of a hollow plunger rod, indicated at 19, extending up the tubular member 18. I

The lower end of the plunger rod 19 is mountedwithin a hollow is ada ted to reciprocate within the cylinder 14 an the bottom of the plunger is rovided with fluid outlet openings indicated y reference numeral 21 which are adapted to admit the flow of fluid into and out of the region in the cylinder below the lplunger, such fluid finding passage through t e plunger and the It will be understood that when hydraulic pressure is applied within the plunger rod 19,

through the plunger rod into the region below the plunger and is eflfective to move the plunger upwardly in the cylinder to the position shown in Fig. 2.

In order to return the plunger to its normal position, pressure is transferred from the member 19 to member 18, which reverses the pressure from the bottom of the plunger to the top of the plunger and forces it down into its normal position. This becomes possible by extending both the members 18 and 19 to the surface and equipping the member 19 with a flexible hydraulic connection.

The lower end of the plunger 20 carries what may be termed a mandrel driving rod 25 which in turn supports a mandrel 26 and when the reciprocation of the plunger is executed as described above, this will in turn move the mandrel 26 correspondingl The mandrel 26 is made polygona in cross section and is illustrated as having three major faces indicated by reference numeral 27 and three so-called minor faces indicated at 28. Each of the major faces 27 is provided with a channel or way which' for the purpose of description will be designated as a holding block guide channel'and is indicated by reference numeral 29.

The holding block guide channel receives holding blocks 30 which are preferably provided with corrugated outer surfaces adapted to engage the inner surface of the casing more securely as best illustrated in Fig. 3.

The holding blocks 30 are adapted to be held in fixed position relative to the cylinder 14 by means of holding block connecting rods or supporting means 33, the ends of which are pivoted to the upper end of the guide holding block is spaced away from and is paris in an upper or perforating position as shown in Fig. 2. The advantages of this construction will be more readilyapparent following the description of the perforating block. It might be mentioned at this point, that in order to safeguard against the possibility of the unit being held up in the casing due to the engagement of the holding blocks with a rojection or the like within the casing, while the unit is being lowered into position, the holding blocks 30 are provided with a rounded lower edge indicated at 39.

The so-called minor surfaces 28 of the mandrel 26 are provided with downwardly and outwardly uniformly tapered ways or called perforating block connecting rods or supporting means indicated by reference numeral 50, the opposite ends of which are connected to the upper end of the perforating blocks and the supporting flange 34in a manner similar to the connecting rods 33, as indicated by reference numerals 51 and 52 respectively.

o It will now be apparent from the foregoing description t at when the parts of the'unit are in the position shown in Fig.

' 1, the organization may be readily lowered into the casing to a point at which it is .desired to place perforations in the walls of the casing, and that when hydraulic pressure is applied. through the supporting tube 18, the plunger 20 and the mandrel 26 will be raised to the position shown in Fi 2.

While the mandrel is being ra1sed, the holding block 30 first moves out and into engagement with the inner wall of the casing and the yertical portion of the mandrel indicated by reference numeral 29' holds the holding block firmly against the inner wall of the casing during the continued upward movement of the mandrel.

Due to the uniform taper of the guide channel 45, the guide block 46 and the cutter member 47 are forced outwardly toward the.

wall of the casing by the upward movement of the mandrel, this movement resulting in the perforation of the casing by the cutter li ember 47 in a manner best illustrated in For the purpose of reducing the friction I between the blocks 30 and 46 and the adjacent surfaces on the mandrel, these blocks are provided with one or more bearing rolls, indicated by reference numerals 55 and 55' respectively.

The roller members 55' which are provided in the cutting blocks 46, are illustrated as being retained therein by means of pins 56, such ins forming the guide pins described al ove which are received by the grooves 49- in the channels 45 for effecting a positive inward and outward movement of the cutter guide blocks.

It has been previously mentioned that it is desirable in using a machine of'this character in connection with stove pipe casing,

to provide means .forguiding the machine into a position such that the perforating block will not be opposite the lap joint 12 in the casing. Such means are best illustrated in Figs. 1, 2 and 4 wherein it will be noted that the lower end of. the mandrel26 is provided with an extension and that this extension has formed therein or thereon a recess or a projection indicated by reference numeral 61 which is adapted to receive a guide member in the form of a sliding pin or trigger 62 held againstrot'ation by means such as ears 63 received by slots 64 and maintained in yieldable engagement with the inner surface of the casing by means such as the coil spring 65.

It will be apparent that when theorganization is lowered into the well the outer surface of the pin 62 rides upon the inner surface of the casing and when the organizav tion is in the osition at which it is desired to perforate t'e casing, it is rotated in the direction of the arrow A in Fig. 4 until the pin 62 comes into engagement with the lap joint 12. It will be understood that further rotation from this point is impossible and the operator therefore knows that the machine is in the proper position for perforation.

Fig. 5 illustrates the manner in which the mandrel 26 may be used in connection with various sizes of holding members and perforating blocks for use in connection with casings of different diameter. A set of larger holding blocks and perforating blocks are shown in dot and dash lines in Fig. 5 and are indicated by reference numerals 30' and 45 respectively. p

. Figs. 6 and 7 illustrate the manner in which the casing is perforated by means of an organization of this character and it willbe noted that the perforation 66 is of a clean out character, its shape being entirely dependent upon the shape of the cutter member 47 which is illustrated as being rectangular. It

will be understood however that various shapes of perforation ma be obtained merely by altering the shape of t e cutter member.

The operation of this device having been indicated in the foregoing description, it will be apparent that this invention embodies an organization of simple form and construction which may be readily assembled and operated for perforating a casing after it has been installed in a well, without the usual undesirable features which ordinarily attend this operation, and it willbe understood that while I have herein described and illustrated one specific embodiment of the invention, that it is not limited to the precise construction set forth but includes within its sco e whatever changes fairly come within t e spirit of the appended claims.

I claim as my invention: 1 1. A casin perforator embodying: a mandrel; a hol ing block and a cutter guide--.

block in sliding engagement with surfaces on said mandrel and adapted to move laterally into engagement with the inner surface of a. casing; supporting means for said mandrel; supporting means for said holding block and said cutter guide-block; and means for eifecting relative transverse movement between said mandrel and said. blocks, the surface of said mandrel which engages said holding block-comprising a tapered section and an untapered section and the surface of said mandrel, which engages said cutter guide-block,

comprising a tapered section which extends beyond the point at which the tapered and untapered section merge on the surface engaging said holding block.

ill

2. A casing perforator embodying: a ta pered mandrel; a plurality of holding blocks slidably mounted on said mandrel; punch members slidably mounted on said mandrel;

means for moving said mandrel longitudinally to move said holding blocks and said punch members transversely, the casing-engaging surface of said holding blocks being eircumferentially shaped and adapted to hold the wall of a casing against distortion during the operation of the punching member.

3. A casing perforator embodying: a mandrel; a plurality of holding blocksslidably mounted on said mandrel and adapted to ride a tapered and an untapered surface; punch members slidably mounted on said mandrel and adapted to ridea strai ht ta red surface; means for movin sai man rel longiholding blocks and tudinally to move sai said punch members transversely, and casingengaging surface of said holdin blocks being circumferentially shaped an adapted to engage the ma'or portion of the inner wall of a casing during the punching operation.

In testimony whereof, I have hereunto set my hand at Los Angeles, California, this 6th day of April, 1929. v

- s ROSCQE MOSS. 

